Some Basic Features of Hydrogen
|Valency||+ 1 or - 1|
|Isotopes of Hydrogen||11H Protium|
Isotopes are atoms of the same element having the same atomic number, but different mass number.
Properties of Hydrogen that Resemble Alkali Metals
Hydrogen atom has one electron in its valence shell like alkali metals.
Hydrogen generally shows + 1 valency like alkali metals.
It readily loses its electron to form a positive ion like other alkali metals.
Combination with non-metals
Hydrogen, like the alkali metals, combines readily with non-metals like halogens, oxygen, sulphur, etc.
Hydrogen is a good reducing agent like other alkali metals.
Properties of Hydrogen that Resemble Halogens
Hydrogen is a non-metal like halogens.
Like halogens, hydrogen is diatomic (H2) whereas metals are monoatomic.
Like halogens, hydrogen may also show 1 valency by accepting an electron. Example: NaH (Sodium hydride)
Nature of compounds
Hydrogen combines with non-metals like carbon, silicon, etc. to from covalent compound like halogens.
Examples: CH4 and CCl4.
In 1766, Henry Cavendish, an English chemist, discovered hydrogen, by treating iron with dilute sulphuric acid. He also proved that when hydrogen is burnt in air, water is the only product obtained. It was "hydrogen", meaning "water producer" (Hydro = water,
gen = generator or producer). Cavendish called this gas "Inflammable gas". Hydrogen has three isotopes namely protium, deuterium and tritium.